Try the MintPlayer PushGithub Step setup

.github/workflows/build-ilspy.yml

@@ -45,7 +45,7 @@ jobs:
         dotnet-version: '3.1.x'
         source-url: https://nuget.pkg.github.com/${{ github.repository_owner }}/index.json
       env:
-        NUGET_AUTH_TOKEN: ${{secrets.GITHUB_TOKEN}}
+        NUGET_AUTH_TOKEN: '%NUGET_AUTH_TOKEN%'
 
     - name: Add msbuild to PATH
       uses: microsoft/setup-msbuild@v1.0.2
@@ -123,6 +123,6 @@ jobs:
 
     - name: Push to Github Packages
       if: github.ref == 'refs/heads/master' && success() && matrix.channel == 'zip' && matrix.configuration == 'release'
-      run: nuget.exe push ICSharpCode.Decompiler\bin\Release\ICSharpCode.Decompiler*.nupkg -NoSymbols -SkipDuplicate
+      run: dotnet nuget push ICSharpCode.Decompiler\bin\Release\ICSharpCode.Decompiler*.nupkg --no-symbols --skip-duplicate
       env:
         NUGET_AUTH_TOKEN: ${{ github.token }}