I gotta say, watching these last couple episodes really made me wish they'd made Nature Chakra a different color.
We already have blue for personal chakra and red for tailed beast chakra, it would have been useful if Nature chakra was yellow or green or something. That way, these "sage jutsu" Rasengans and Tailed Beast Bombs would have at least looked visually distinctive from the normal moves.
There's nothing he can really do. He doesn't know Sage Jutsu.
Unless Juugo gives him a new Cursed Seal or something, he can't even hurt Obito.