Other questions to ask a nursery:
Do they have access to the outdoors? How often do they get access to the outdoors, is it at set times or can they go out when they choose? (The latter being best practice for early years IIRC, but not always logistically possible).
What do the children do all day? (Personally I would be listening out for lots of chance for play and creative activities, and the ability to choose what they play with, and not an overly structured environment).
What's the best thing about this nursery? (I like to ask open ended questions, they can be very telling sometimes!)
Where do they nap?
How many different adults are the children looked after by? Do they have an adult, like a key worker, who looks out for them specifically?
Do staff tend to stay at the nursery for a long time? How long has their longest member of staff been there?
Are the children in separate rooms (e.g. a baby room) or all together? How many children are at the nursery, and how many in their group?
Do they prepare lunch (if so, what are the options / what's a typical meal like)?
Probably loads of other questions!
Your gut instinct is very very important IMO and should not be ignored.