you could create a list in iNat and use the Add Batch function to add a bunch of taxa. from there, if you don’t actually need the project structure, you could just filter by your list_id.
if you need the project structure, then here’s a way to add a bunch of taxa from a list to a collection project: https://forum.inaturalist.org/t/moving-a-list-to-a-project/64938/2.