I’ve lived in Bangalore for over five years.
I may have visited Nandi Hills once a year...just incidently. The first trip was more out of curiousity since I am a history student and having to see one of Tipu Sultan’s summer retreats was a delight.It was a bit of a disappointment in the end.
To begin with - there is nothing there apart from some interesting hairpin bends that lead to the hotel that stands there now.There are some monuments and if I remember correctly - some cannons from the yester years.
There is an uphill walk that takes you to a point protruding out of the hills today famously called Tipu’s Drop - where history records it as a place where prisoners were thrown off for crimes they committed !! Quite a few suicides have also taken place here so you will have to contend with a heavily barricaded point !!!
Ideal to spend a day but not worth staying over for the night.
Probably a one time visit will do you in.
Local Bangaloreans take to the spot simply to beat the city lights and enjoy a good drive when the weather is good and the company is exciting.
For details : https://hotelskarnataka.com/html/nandi-hills.htm