Hello @amyk1 and @mcint29! Thanks for coming back here for help on this subject. It can definitely be a bit tricky so let me offer some clarification. :)

If the expense is already being mapped in Box 1 for 1099 NEC, it won't let you map it again in Box 7 for 1099 MISC. New or separate accounts are necessary for both NEC and MISC.  Here's a great article that explains this: How to modify your chart of accounts for your 1099-MISC and 1099-NEC filing. 

If you have any more questions, please don't hesitate to reply to this post. We're all happy to help in any way we can!