Probably not resilient enough to deal with copies that gain abilities, but oh well. I mostly wanted to discuss reproduction on Namekkos.

Sentient creatures can obviously build new robots, but what about all of the other mechanical fauna on Namekkos? They reproduce the same way, basically. If you consider the construction of a bird's nest or a beehive, you might be surprised that such seemingly simple animal can build something that intricate. However, it's all done via instinct; the animal doesn't need to consciously know what it's doing.

In the same way, when animal constructs on Namekkos prepare to reproduce, they collect materials and build a robot without understanding why. This is also a source of "genetic" variation, which causes the organisms to evolve over time. Though realistically this system may not have been able to arise naturally, that's okay, since (plot twist!) it didn't on Namekkos either! Its biosphere is an artificial construction of an organic civilization long since past. (Or is it?)

If you get a 2/2 blue token from Wand of the Elements and the 8/8 token from Grove of the Guardian, both tokens are named "Elemental". What happens when you try to activate the ability with those?

Yeah, this card doesn't really work. There probably isn't a good way to fix it, unless it makes a copy of one of the creatures.

Well "non-token" might have been needed anyway to keep the card in check. I could imagine a player with tons of creature kill getting frustrated, because he can never kill enough creatures to stop the Nest from working.

Which is basically Pack Rat. This wouldn't be quite as bad as that card (in Limited, anyway).