diff --git a/nix/package.nix b/nix/package.nix
index b904333f5..08623bde2 100644
--- a/nix/package.nix
+++ b/nix/package.nix
@@ -52,6 +52,7 @@ buildNpmPackage rec {
   # Default hash lives in nix/npm-deps.hash (see arg default above).
   # CI auto-updates that file when package-lock.json changes (see .github/workflows/).
   inherit npmDepsHash;
+  npmDepsFetcherVersion = 2;
 
   # Prevent onnxruntime-node's install script from running during automatic
   # npm rebuild (it tries to download from api.nuget.org, which fails in the sandbox).
diff --git a/scripts/update-nix.sh b/scripts/update-nix.sh
index 108cd0d60..b33cd4f99 100755
--- a/scripts/update-nix.sh
+++ b/scripts/update-nix.sh
@@ -35,7 +35,7 @@ NIXPKGS_URL="$(node -p "
 STDERR_LOG="$(mktemp)"
 trap "rm -f '$STDERR_LOG'" EXIT
 
-if ! NEW_HASH="$(nix shell "${NIXPKGS_URL}#prefetch-npm-deps" -c prefetch-npm-deps "$LOCK_FILE" 2>"$STDERR_LOG")"; then
+if ! NEW_HASH="$(NIX_NPM_FETCHER_VERSION=2 nix shell "${NIXPKGS_URL}#prefetch-npm-deps" -c prefetch-npm-deps "$LOCK_FILE" 2>"$STDERR_LOG")"; then
   echo "ERROR: prefetch-npm-deps failed:" >&2
   tail -20 "$STDERR_LOG" >&2
   exit 1