These are good answers, but I would also suggest checking the NUnit documentation, since the setup might change over time: https://docs.nunit.org/articles/nunit/technical-notes/usage/Trace-and-Debug-Output.html

Today, when I was looking at the same problem in VS 2022, I got it working by

a) Adding the code in the 2nd example from the page page referenced:

    [OneTimeSetUp]
    public void StartTest()
    {
        if (!Trace.Listeners.OfType<ProgressTraceListener>().Any())
            Trace.Listeners.Add(new ProgressTraceListener());
    }

b) Change the output in from "Debug" to "Tests" in Visual Studio:

c) Then I was able to see the Console.WriteLine("Whatever!") output that's inside my test.