diff --git a/pkgs/by-name/st/steam-tui/package.nix b/pkgs/by-name/st/steam-tui/package.nix
index 75d3523eb37e..2c8001940704 100644
--- a/pkgs/by-name/st/steam-tui/package.nix
+++ b/pkgs/by-name/st/steam-tui/package.nix
@@ -43,7 +43,7 @@ rustPlatform.buildRustPackage rec {
 
   checkFlags = [ "--skip=impure" ];
 
-  PKG_CONFIG_PATH = "${openssl.dev}/lib/pkgconfig";
+  env.PKG_CONFIG_PATH = "${openssl.dev}/lib/pkgconfig";
 
   meta = {
     description = "Rust TUI client for steamcmd";