diff --git a/pkgs/development/python-modules/nine/default.nix b/pkgs/development/python-modules/nine/default.nix
index d5191719f774..b154b82c962f 100644
--- a/pkgs/development/python-modules/nine/default.nix
+++ b/pkgs/development/python-modules/nine/default.nix
@@ -2,18 +2,21 @@
   lib,
   buildPythonPackage,
   fetchPypi,
+  poetry-core,
 }:
 
 buildPythonPackage rec {
   pname = "nine";
   version = "1.2.0";
-  format = "setuptools";
+  pyproject = true;
 
   src = fetchPypi {
     inherit pname version;
     sha256 = "sha256-NSp9/hGVO39NEoqEeuAe50sdnfyVL4Lzyx8dvUHmbKk=";
   };
 
+  build-system = [ poetry-core ];
+
   meta = with lib; {
     description = "Let's write Python 3 right now!";
     homepage = "https://github.com/nandoflorestan/nine";