Breastfeeding & TDEE

How much your baby eats does not matter for weight loss purposes. Estimate 300 calories for a young baby, up to 500 for an older baby, assuming you nurse on demand.
The simplest I would suggest is to eat at your maintenance, whatever this is. If you do not account at all for breastfeeding, and do not set a weight loss goal either, then breastfeeding will create the deficit for you and you will not be starving either. If you see you are not losing after a few weeks, then lower by 200 calories or so. If you are losing too fast, increase by 200 calories and see what happens.

When my baby was young, I added 500 calories a day to account for breastfeeding. Once he turned 6 months and started eating solid food I decreased to 300 calories a day extra. More than likely when he gets closer to 1 I'll decrease it to 200 or so, depending on how often he's nursing at that point. The more they nurse, the more calories you need. But it's all sort of a guess. Try 500 extra a day for 3-4 weeks and see how much you lose. If you aren't losing much, you could drop 100 calories a day. Aim for losing 1 pound a week so you don't lose too quickly. I've managed to lose 62 lbs since my 8 month old was born so it is possible to lose weight while maintaining your supply!!