diff --git a/.golangci.yml b/.golangci.yml
index 6d458a5b7..bc720ccf4 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -17,6 +17,7 @@ linters:
     - errcheck
     - gosimple
     - gocognit
+    - nilerr
     - whitespace
     - misspell
 
diff --git a/beacon-chain/core/helpers/sync_committee.go b/beacon-chain/core/helpers/sync_committee.go
index 1066547c7..23cfb2d3a 100644
--- a/beacon-chain/core/helpers/sync_committee.go
+++ b/beacon-chain/core/helpers/sync_committee.go
@@ -36,7 +36,7 @@ func IsCurrentPeriodSyncCommittee(
 	if err == cache.ErrNonExistingSyncCommitteeKey {
 		val, err := st.ValidatorAtIndex(valIdx)
 		if err != nil {
-			return false, nil
+			return false, err
 		}
 		committee, err := st.CurrentSyncCommittee()
 		if err != nil {
@@ -73,7 +73,7 @@ func IsNextPeriodSyncCommittee(
 	if err == cache.ErrNonExistingSyncCommitteeKey {
 		val, err := st.ValidatorAtIndex(valIdx)
 		if err != nil {
-			return false, nil
+			return false, err
 		}
 		committee, err := st.NextSyncCommittee()
 		if err != nil {
@@ -100,7 +100,7 @@ func CurrentPeriodSyncSubcommitteeIndices(
 	if err == cache.ErrNonExistingSyncCommitteeKey {
 		val, err := st.ValidatorAtIndex(valIdx)
 		if err != nil {
-			return nil, nil
+			return nil, err
 		}
 		committee, err := st.CurrentSyncCommittee()
 		if err != nil {
@@ -134,7 +134,7 @@ func NextPeriodSyncSubcommitteeIndices(
 	if err == cache.ErrNonExistingSyncCommitteeKey {
 		val, err := st.ValidatorAtIndex(valIdx)
 		if err != nil {
-			return nil, nil
+			return nil, err
 		}
 		committee, err := st.NextSyncCommittee()
 		if err != nil {
diff --git a/beacon-chain/core/helpers/sync_committee_test.go b/beacon-chain/core/helpers/sync_committee_test.go
index 21bc6040f..c3860d5de 100644
--- a/beacon-chain/core/helpers/sync_committee_test.go
+++ b/beacon-chain/core/helpers/sync_committee_test.go
@@ -94,7 +94,7 @@ func TestIsCurrentEpochSyncCommittee_DoesNotExist(t *testing.T) {
 	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
 
 	ok, err := IsCurrentPeriodSyncCommittee(state, 12390192)
-	require.NoError(t, err)
+	require.ErrorContains(t, "index 12390192 out of range", err)
 	require.Equal(t, false, ok)
 }
 
@@ -176,7 +176,7 @@ func TestIsNextEpochSyncCommittee_DoesNotExist(t *testing.T) {
 	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
 
 	ok, err := IsNextPeriodSyncCommittee(state, 120391029)
-	require.NoError(t, err)
+	require.ErrorContains(t, "index 120391029 out of range", err)
 	require.Equal(t, false, ok)
 }
 
@@ -273,7 +273,7 @@ func TestCurrentEpochSyncSubcommitteeIndices_DoesNotExist(t *testing.T) {
 	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
 
 	index, err := CurrentPeriodSyncSubcommitteeIndices(state, 129301923)
-	require.NoError(t, err)
+	require.ErrorContains(t, "index 129301923 out of range", err)
 	require.DeepEqual(t, []primitives.CommitteeIndex(nil), index)
 }
 
@@ -356,7 +356,7 @@ func TestNextEpochSyncSubcommitteeIndices_DoesNotExist(t *testing.T) {
 	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
 
 	index, err := NextPeriodSyncSubcommitteeIndices(state, 21093019)
-	require.NoError(t, err)
+	require.ErrorContains(t, "index 21093019 out of range", err)
 	require.DeepEqual(t, []primitives.CommitteeIndex(nil), index)
 }
 
diff --git a/beacon-chain/rpc/eth/node/node.go b/beacon-chain/rpc/eth/node/node.go
index b64038bee..2ab5ea0a8 100644
--- a/beacon-chain/rpc/eth/node/node.go
+++ b/beacon-chain/rpc/eth/node/node.go
@@ -301,6 +301,7 @@ func (ns *Server) GetHealth(ctx context.Context, _ *emptypb.Empty) (*emptypb.Emp
 	if ns.SyncChecker.Syncing() || ns.SyncChecker.Initialized() {
 		if err := grpc.SetHeader(ctx, metadata.Pairs(grpcutil.HttpCodeMetadataKey, strconv.Itoa(http.StatusPartialContent))); err != nil {
 			// We return a positive result because failing to set a non-gRPC related header should not cause the gRPC call to fail.
+			//nolint:nilerr
 			return &emptypb.Empty{}, nil
 		}
 		return &emptypb.Empty{}, nil
diff --git a/beacon-chain/rpc/testutil/mock_blocker.go b/beacon-chain/rpc/testutil/mock_blocker.go
index dac5a8851..904d63ea4 100644
--- a/beacon-chain/rpc/testutil/mock_blocker.go
+++ b/beacon-chain/rpc/testutil/mock_blocker.go
@@ -22,6 +22,7 @@ func (m *MockBlocker) Block(_ context.Context, b []byte) (interfaces.ReadOnlySig
 	}
 	slotNumber, parseErr := strconv.ParseUint(string(b), 10, 64)
 	if parseErr != nil {
+		//nolint:nilerr
 		return m.BlockToReturn, nil
 	}
 	return m.SlotBlockMap[primitives.Slot(slotNumber)], nil
diff --git a/beacon-chain/sync/initial-sync/blocks_fetcher.go b/beacon-chain/sync/initial-sync/blocks_fetcher.go
index 3b59eee44..6b1297c52 100644
--- a/beacon-chain/sync/initial-sync/blocks_fetcher.go
+++ b/beacon-chain/sync/initial-sync/blocks_fetcher.go
@@ -296,7 +296,7 @@ func (f *blocksFetcher) fetchBlocksFromPeer(
 		blocks, err := f.requestBlocks(ctx, req, peers[i])
 		if err == nil {
 			f.p2p.Peers().Scorers().BlockProviderScorer().Touch(peers[i])
-			return blocks, peers[i], err
+			return blocks, peers[i], nil
 		} else {
 			log.WithError(err).Debug("Could not request blocks by range")
 		}
diff --git a/testing/endtoend/components/eth1/transactions.go b/testing/endtoend/components/eth1/transactions.go
index 9a8bb6c13..1d86a396a 100644
--- a/testing/endtoend/components/eth1/transactions.go
+++ b/testing/endtoend/components/eth1/transactions.go
@@ -110,14 +110,13 @@ func SendTransaction(client *rpc.Client, key *ecdsa.PrivateKey, f *filler.Filler
 		g.Go(func() error {
 			tx, err := txfuzz.RandomValidTx(client, f, sender, nonce+index, gasPrice, nil, al)
 			if err != nil {
-				return nil
+				return err
 			}
 			signedTx, err := types.SignTx(tx, types.NewLondonSigner(chainid), key)
 			if err != nil {
-				return nil
+				return err
 			}
-			err = backend.SendTransaction(context.Background(), signedTx)
-			return nil
+			return backend.SendTransaction(context.Background(), signedTx)
 		})
 	}
 	return g.Wait()
diff --git a/validator/rpc/beacon.go b/validator/rpc/beacon.go
index 841fc96a3..3c41b7048 100644
--- a/validator/rpc/beacon.go
+++ b/validator/rpc/beacon.go
@@ -70,6 +70,7 @@ func (s *Server) registerBeaconClient() error {
 func (s *Server) GetBeaconStatus(ctx context.Context, _ *empty.Empty) (*validatorpb.BeaconStatusResponse, error) {
 	syncStatus, err := s.beaconNodeClient.GetSyncStatus(ctx, &emptypb.Empty{})
 	if err != nil {
+		//nolint:nilerr
 		return &validatorpb.BeaconStatusResponse{
 			BeaconNodeEndpoint: s.nodeGatewayEndpoint,
 			Connected:          false,
diff --git a/validator/rpc/health.go b/validator/rpc/health.go
index 5d6e24402..b20dcac95 100644
--- a/validator/rpc/health.go
+++ b/validator/rpc/health.go
@@ -19,6 +19,7 @@ import (
 func (s *Server) GetBeaconNodeConnection(ctx context.Context, _ *emptypb.Empty) (*validatorpb.NodeConnectionResponse, error) {
 	syncStatus, err := s.syncChecker.Syncing(ctx)
 	if err != nil || s.validatorService.Status() != nil {
+		//nolint:nilerr
 		return &validatorpb.NodeConnectionResponse{
 			GenesisTime:        0,
 			BeaconNodeEndpoint: s.nodeGatewayEndpoint,