diff --git a/nixos/modules/services/monitoring/prometheus/exporters/nginx.nix b/nixos/modules/services/monitoring/prometheus/exporters/nginx.nix
index 5ee8c346be1d..3cdd7866bd4d 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/nginx.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/nginx.nix
@@ -47,7 +47,7 @@ in
       ExecStart = ''
         ${pkgs.prometheus-nginx-exporter}/bin/nginx-prometheus-exporter \
           --nginx.scrape-uri '${cfg.scrapeUri}' \
-          --nginx.ssl-verify ${toString cfg.sslVerify} \
+          --nginx.ssl-verify ${boolToString cfg.sslVerify} \
           --web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
           --web.telemetry-path ${cfg.telemetryPath} \
           --prometheus.const-labels ${concatStringsSep "," cfg.constLabels} \