I'm not a fan of chilli, so I'd be a bit disappointed that there weren't other offerings. Generally I think it's nice to serve at least 2 choices.Don't forget you need to cater for vegetarian/vegan/dairy free/gluten free/ nut allergy/ diabetics etc etc too. Also are there children going? I'd say only one option of spicy food is pretty brave if so.
What are you planning for pudding? Again, you'll need to plan things that cater for all the food preferences.
Personally, if I wanted to do for that many, I'd go for cold buffet mostly bought from Morrisons /Sainsbury's/Waitrose food to order, with a few things home made to add to the mix.
Even if it's "bring a bottle", I think you still need to provide tea, coffee, soft drinks and a few bottles of wine (Tesco have currently have 25% off 6+,so you could pick up 12 red and 12 white bottles of plonk for under £100) and beers to get the party going. In my experience, guests bring a bottle as a contribution, but not ever enough that you can get away without providing some.
Also you'll need crockery, cutlery, tablecloths etc too.
It's possible, but it's going to be very hard work to do it well, and will probably work out more expensive than just buying it in or getting caterers in.
I'm sorry if I sound a bit negative, bit I'm currently planning a smaller party myself, and it's s hell of a lot more complicated than just bunging a chilli in the slow cooker