I need advice for my friend who is being harassed.

(I gotta tell y’all the drama before you understand) so long story short:

Victoria (my bff) and Nicole (ex friend) don’t get along. We all used to be friends in HS but that ended years ago. Anyway, Nicole is married to a guy named Chris and Chris used to be very good friends with Victoria. Anyway, Nicole turned out to be a bit psycho and jealous and she harasses Victoria on the daily, texting her and Victoria’s boyfriend from unknown numbers saying that Victoria is cheating on him and all that. Which she hasn’t had contact with that Chris guy in months. Victoria has had enough, this has been going on for maybe over a year now, and she had a mental breakdown yesterday and is looking into some type of legal way to get Nicole in trouble and to leave them alone.

What steps need to be taken? We live in TX btw

Also: Victoria’s mother in law lives down the street of Nicole’s house and my friend is thinking of calling the police if she sees that Nicole is home. Is that a good idea?