A Nepenthes seedling looks like a tiny green sprout with two leaf
blades on it. The leaf blades aren't very big. If you take a
magnifying glass and look at the ends of the leaf blades, if
you're growing it with enough warmth, the leaf blades may have
a little round green dot on the end. This will be an immature
pitcher that has a tiny depression in it. It will not have a cap
or much in the way of hairs or teeth, just a small depression in
a tiny round circle. That's how I was able to tell with
Nepenthes Khasiana seedlings. You may also have to wait until
you see a third leaf. That will have the Nepenthes look.
---Steve