Tit's nest on balcony

Hi, We had a bird house fixed on our balcony wall for several years. This season, a family of Tit bird (i think) elected to nest in there. Very pleased to help with sheltering, we are wondering how to make their stay best. They now got kids as we see them flying back and forth very often with food to given them.

We keep the use of balcony minimal, but wonder if having a meal outside is a big disturbance/stress for them or not? Seems they don't want to get in and out their house if someone's on the balcony.

Anything else we can do to help them, besides not interfering and watching them happily from our living room inside (and clean our window for future pictures..)?