I felt the same - no idea what to ask! i viewed when heavily pregnant and hadn’t really been around kids much before.
In the end, I walked in and loved the environment - I didn’t think I knew what I was looking for! It was clean, colourful, the equipment looked new and there was lots of it. The children were well behaved, clean(!) and the staff were very friendly. I also saw the staff interacting with the children and liked how they were doing it. They weren’t afraid to “discipline” the children in front of me either. (Small things like, “please don’t run, I’ve told you to put that back etc…)
in terms of questions to ask, I didn’t have a child to ask about, so a lot of my questions were around admin like “when are fees due, what’s included etc”. The nursery could tell I didn’t know what to ask, so volunteered information such as: “we go outside every day, we follow the baby sleep routine, we do these activities” and she volunteered information on how they cater for children with allergies and she showed me all their menus.
has your Baby been born yet? If not, it might be hard to ask questions about a hyperthetical baby, but if it has I’d ask about sleep routines they carry out, are they happy to help with potty training, what does the day look like.