Yes and no. Yes, you can put your kitchen scraps into your potting soil bin and yes they will compost. But no, you shouldn't, and here's why:

It's important to have a separate compost bin to empty your kitchen scraps into. When potting your plants you will want to have fresh soil to mix with a third compost. You will want to have a better idea of what stage your compost is in so you can mix and move it accordingly. It's preferable to use your potting soil as an addition to your kitchen scraps you bring to your in weekly (or whatever your schedule may be).