Nursing to sleep

Is it a bad habit to allow baby to nurse anytime she wakes thru the night? Should I offer a paci instead? But then won’t she wake everytime she wants it also?! She is 4 months now. She was sleeping extremely well the 1st three months and now for the past 3 weeks she is waking constantly after I put her to bed. I let her nurse and she goes to sleep but wakes again 1.5-2 hours later. Not sure what to do or change to get her back to sleeping longer.

*I do not want to bed share but with these frequent wakings it’s pretty much what’s happening in order for me to get any amount of sleep.