Example of a Regression Test & Unit Test - Windows Forms LOB application

We have a LOB Winforms application that follows MVP pattern as much as possible.

At each new release, we want to test against any regression.

Current approach is that every time a tester a bug/crash, we reproduce the bug, then insert a test using NUnit. Usually this test tries to reproduce the chain of actions followed by the user, so we end up with tests like : MenuX_OperationY_buttonDoZ_Click_ERROR_DESCRIPTION()

The test usually prepares the context, load data, and execute the action clicked by the user to reproduce the bug. Then the bug is fixed and the test is rerun. And so on ..., until we have a large base of existing (regression ?) tests. Example of such a test is :

[Test]
public void MenuX_OperationY_buttonDoZ_Click_ERROR_DESCRIPTION()
{
    // The presenter prepares Context & Load Data associated with Menu X
    PrsMenuX.PrepareContext();
    PrsMenuX.LoadData();

    // Do Operation Y
    PrsMenuX.OperationY();

    // Click on Button Do Z
    try
    {
        PrsMenuX.ButtonDoZ_Click();
    }
    catch (Exception ex)
    {
        Assert.Fail(ex.Message);
    }
}

So my question, is it the right approach ? is NUnit the right tool for this, and how to improve this ? Should the tests reproduces the user's actions or should we unit-test only low level functions that composes each user's action ?