The spell Creation description states I create a nonliving object. Can I create things like health potions and Poisons as long as I have a potion or poison to base it off of?
You can't create potions in this way, because they are magical in nature. They definitely don't come under 'nonliving object of vegetable matter' or under 'mineral objects'.
To create poisons, on the other hand, might be possible. The examples given for 'nonliving object of vegetable matter' are "soft goods" (whatever that means), rope, wood, or something similar. So this doesn't seem to be an intended use for this spell, but if you can find a poison that is made solely out of vegetable material then I can't find a reason to disallow it. Of course, none of the poisons currently available explicitly come from plants, so this might be difficult.
Note that this creates an extremely strange interaction: What happens if you poison someone with a poison that ceases to exist while the person is still poisoned? It's a complicated enough question to:
a) Be worth a separate question of its own
b) Suggest that this really isn't something that's meant to be able to happen.