I think ASTAP is probably the most popular of plate solving for N.I.N.A. users however you can use Platesolve3 if you prefer :-
https://nighttime-imaging.eu/docs/ma...g/#platesolve3
You'd set your PlateSolve3 settings here (circled in red).
P.S. Outta curiosity, does that mean you've solved your N.I.N.A. SiTech ASCOM connectivity now?