diff --git a/hacking/nix/scope/default.nix b/hacking/nix/scope/default.nix
index 300d6f6c8..7ffa10063 100644
--- a/hacking/nix/scope/default.nix
+++ b/hacking/nix/scope/default.nix
@@ -98,6 +98,14 @@ superCallPackage ../rust-utils {} self //
     in
       toolchain.withComponents filteredComponents;
 
+  parseStructuredChannel = unstructuredChannel:
+    let
+      parts = builtins.match ''(nightly)-(.*)'' unstructuredChannel;
+    in
+      if parts == null
+      then { channel = unstructuredChannel; date = null; }
+      else { channel = lib.elemAt parts 0; date = lib.elemAt parts 1; };
+
   defaultRustEnvironment =
     let
       inherit (scopeConfig.rustEnvironmentSelector) tracks upstream;
diff --git a/hacking/nix/scope/kani/default.nix b/hacking/nix/scope/kani/default.nix
index a3c3dfed9..eb78c57c3 100644
--- a/hacking/nix/scope/kani/default.nix
+++ b/hacking/nix/scope/kani/default.nix
@@ -16,7 +16,8 @@
 , crateUtils
 , vendorLockfile
 , sources
-, fenix
+, assembleRustToolchain
+, parseStructuredChannel
 , elaborateRustEnvironment
 , mkDefaultElaborateRustEnvironmentArgs
 , mkMkCustomTargetPathForEnvironment
@@ -27,20 +28,16 @@ let
 
   rustToolchainAttrs = builtins.fromTOML (builtins.readFile (src + "/rust-toolchain.toml"));
 
-  rustToolchain = fenix.fromToolchainFile {
-    file = crateUtils.toTOMLFile "rust-toolchain.toml" (crateUtils.clobber [
-      rustToolchainAttrs
-      {
-        toolchain.components = rustToolchainAttrs.toolchain.components ++ [ "rust-src" ];
-      }
-    ]);
+  inherit (rustToolchainAttrs.toolchain) channel;
+
+  rustToolchain = assembleRustToolchain (parseStructuredChannel channel // {
     sha256 = "sha256-opDDHyN+Xa9kcjdHwGl3IpBsUw7ikGU+Ng00JeCdkMA=";
-  };
+  });
 
   rustEnvironment = lib.fix (self: elaborateRustEnvironment (mkDefaultElaborateRustEnvironmentArgs {
     inherit rustToolchain;
   } // {
-    inherit (rustToolchainAttrs.toolchain) channel;
+    inherit channel;
     mkCustomTargetPath = mkMkCustomTargetPathForEnvironment {
       rustEnvironment = self;
     };
diff --git a/hacking/nix/scope/verus/default.nix b/hacking/nix/scope/verus/default.nix
index 5fe844282..b1da14fc4 100644
--- a/hacking/nix/scope/verus/default.nix
+++ b/hacking/nix/scope/verus/default.nix
@@ -23,15 +23,17 @@ let
 
   rustToolchainAttrs = builtins.fromTOML (builtins.readFile (src + "/rust-toolchain.toml"));
 
+  inherit (rustToolchainAttrs.toolchain) channel;
+
   rustToolchain = assembleRustToolchain {
-    channel = "1.76.0";
+    inherit channel;
     sha256 = "sha256-e4mlaJehWBymYxJGgnbuCObVlqMlQSilZ8FljG9zPHY=";
   };
 
   rustEnvironment = lib.fix (self: elaborateRustEnvironment (mkDefaultElaborateRustEnvironmentArgs {
     inherit rustToolchain;
   } // {
-    inherit (rustToolchainAttrs.toolchain) channel;
+    inherit channel;
     backwardsCompatibilityHacks = {
       outDirInsteadOfArtifactDir = true;
       noLibraryWorkspace = true;