Do not issue a 1099-NEC because the payments you're making aren't for a contractor and aren't income from self employment to the previous business owner. What you bought is a Sec 197 intangible in the form of a book of business or accounts and those are amortized over 15 years. Lawyers should have rep'd both sides in this transaction.
Thank you so much for the advice - doing research on how to amortize Section 197 assets. Will likely get some lawyers involved. I worked for my senior agent for 8 years as a 1099 employee and when he passed away in March 2020 I agreed to pay his widow to retain/take over the book of business. Since we were close and she was grieving we skipped what seems to be some essential steps that will need to be corrected now.