Crafting both pharmaceutical items and industrial items count towards this.
In the lodge in New Atlantis, you can craft both types in the basement at their relevant workbenches.
Once you have enough credits, (i had like 90k credits) make a save just for this and spend all of your money on resources.
I used the mercantile store just past the city entrance when you land at new atlantis.
Then run to the lodge while over encumbered via taking the tram to MAST or fast travel to the lodge.
Spam crafting.
If you need more resources, wait until the mercantile store refreshes stock (not sure how long it takes) and rinse and repeat.
You can somewhat check your status of how many you crafted by going into your character menu, then to status (y button on default controls), then go to crafting, and and check "chems crafted". Industrial items don't seem to have a menu item to track them?
Popped right when I hit 100 items.
Once done, reload your normal save.