diff --git a/modules/nginx.nix b/modules/nginx.nix
index 8da5190..143e14f 100644
--- a/modules/nginx.nix
+++ b/modules/nginx.nix
@@ -9,7 +9,7 @@ in
 
     enableACME = lib.mkEnableOption "acme cert generation and use";
 
-    certDomains = lib.mkOptions {
+    certDomains = lib.mkOption {
       description = "additional domains to register with the ACME cert";
       default = [ ];
       type = with lib.types; listOf str;