Ok so you need to do 2 things if you want her to sleep through the night
1. Get her on an age appropriate schedule
Aim for approximately 11 hour night, 5 hours before nap and 6 hours after nap. Some kids will sleep longer but this is a good goal.
Stick to the bedtime no matter what regardless of how the day (nap) went
2. Independent sleep!
Your baby does not know how to fall asleep on her own, only with a bottle. She is waking up during the night and needs a bottle to fall back asleep.
You will need to set up a good bedtime routine so she knows it’s bedtime and then put her in the crib awake and leave the room so she can learn to fall asleep alone.
At 15 months kids don’t need bottles at all, and it really shouldn’t be the way they go to sleep.
Thanks so much to u and everyone else for the responses!!