"The software does not generate a specific form for 1099-NEC."

And which software would this be?

The 1099-NEC is informational; it doesn't go "in" the Sched C. You might not ever get a 1099-NEC, but if your client is in business, all business activity gets reported on the Sched C. You don't only report the forms reported to the client; you report everything.