diff --git a/nix/build.nix b/nix/build.nix
index 09dbe12f..1a115f7d 100644
--- a/nix/build.nix
+++ b/nix/build.nix
@@ -79,15 +79,20 @@ beamPackages.mixRelease {
 
   # Install MIB files to the release
   postInstall = ''
-    # Copy MIB files directory
-    if [ -d "$src/priv/mibs" ]; then
-      mkdir -p $out/lib/towerops-${version}/priv/mibs
-      cp -r $src/priv/mibs/* $out/lib/towerops-${version}/priv/mibs/
-    fi
+    # Find the release directory (mixRelease creates lib/<name>-<version>)
+    RELEASE_DIR=$(find $out/lib -maxdepth 1 -type d -name "towerops-*" | head -1)
 
-    # Ensure NIF is in the release
-    mkdir -p $out/lib/towerops-${version}/priv
-    cp ${towerops-nif}/lib/towerops_nif.so $out/lib/towerops-${version}/priv/
+    if [ -n "$RELEASE_DIR" ]; then
+      # Copy MIB files directory
+      if [ -d "$src/priv/mibs" ]; then
+        mkdir -p $RELEASE_DIR/priv/mibs
+        cp -r $src/priv/mibs/* $RELEASE_DIR/priv/mibs/
+      fi
+
+      # Ensure NIF is in the release
+      mkdir -p $RELEASE_DIR/priv
+      cp ${towerops-nif}/lib/towerops_nif.so $RELEASE_DIR/priv/
+    fi
   '';
 
   meta = {