The description and supporting info provided for a chain restaurant in a small town need to convince reviewers and Niantic that it is a great place to be social at.
Even with a unique, locally-owned business/restaurant, you can’t just say that it’s a popular place in your area; there needs to be more provided that it is a popular place and meets criteria. I live near a local dinar that’s locally-owned, family friendly, makes their food fresh and bakes their own desserts, and has been around for over 40 years. It’s a great place to grab a meal at anytime of the day, or just stop by for some coffee and dessert. I made sure to highlight many of these aspects in the description, and others in the supporting info, and it was approved by the community.
Basically, with restaurants and businesses, it’s all about how you sell them to the community and Niantic. I know not everyone has done sales work, but knowing a little about selling has seemed to help with my nominations.
There is now some good information on generic/non-generic businesses, including chain businesses in rural areas, here in the forums and in the help center.