diff --git a/.eslintrc.json b/.eslintrc.json
index 5966041..ac2dfef 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -60,6 +60,7 @@
     "@typescript-eslint/prefer-for-of": "warn",
     "@typescript-eslint/prefer-function-type": "warn",
     "@typescript-eslint/prefer-includes": "error",
+    "@typescript-eslint/prefer-nullish-coalescing": "error",
     "@typescript-eslint/prefer-string-starts-ends-with": "error",
     "@typescript-eslint/promise-function-async": "error",
     "@typescript-eslint/require-array-sort-compare": "error",
diff --git a/src/helpers.ts b/src/helpers.ts
index 826e9d9..4fcc011 100644
--- a/src/helpers.ts
+++ b/src/helpers.ts
@@ -15,7 +15,7 @@ export function tailLog(daemonDir: string): Tail {
 
 export async function netrcPath(): Promise<string> {
   const expectedNetrcPath = path.join(
-    process.env["RUNNER_TEMP"] || os.tmpdir(),
+    process.env["RUNNER_TEMP"] ?? os.tmpdir(),
     "determinate-nix-installer-netrc",
   );
   try {
@@ -24,7 +24,7 @@ export async function netrcPath(): Promise<string> {
   } catch {
     // `nix-installer` was not used, the user may be registered with FlakeHub though.
     const destinedNetrcPath = path.join(
-      process.env["RUNNER_TEMP"] || os.tmpdir(),
+      process.env["RUNNER_TEMP"] ?? os.tmpdir(),
       "magic-nix-cache-netrc",
     );
     try {