diff --git a/nixos/modules/services/security/tor.nix b/nixos/modules/services/security/tor.nix
index f1e27cbaa256..0c6002c396b1 100644
--- a/nixos/modules/services/security/tor.nix
+++ b/nixos/modules/services/security/tor.nix
@@ -1055,7 +1055,11 @@ in
           options.MaxClientCircuitsPending = optionInt "MaxClientCircuitsPending";
           options.NATDPort = optionIsolablePorts "NATDPort";
           options.NewCircuitPeriod = optionInt "NewCircuitPeriod";
-          options.Nickname = optionString "Nickname";
+          options.Nickname = lib.mkOption {
+            type = with lib.types; nullOr (strMatching "^[a-zA-Z0-9]{1,19}$");
+            default = null;
+            description = (descriptionGeneric "Nickname");
+          };
           options.ORPort = optionORPort "ORPort";
           options.OfflineMasterKey = optionBool "OfflineMasterKey";
           options.OptimisticData = optionBool "OptimisticData"; # default is null and like "auto"