Tips and tricks

You will have to edit the template accessible from the MAMP PRO > File > Edit Template > Nginx

you should add

location /wp { index index.php; try_files $uri $uri/ /wp/index.php?$args; }

under the server which interests you

you can also place it under your location/ for multiple installations

        location / {
            try_files       $uri $uri/ /wptest/index.php?$args /wp2/index.php?$args; }