It is quite easy to do it yourself. As mentioned, if your flat nocks have threads, screw in a field tip and heat it till the glue melts enough to allow the nock to come out. Get some acetone and clean out the inside of the shaft. Insert the lighted nock of your choice making sure you have the current ID of your shaft.
I prefer Lumenoks, Nock Outs, and Firenocks(very expensive). Nufletch Ignitors are pretty good as well.
I support all hunters, regardless of weapon or technique!