>>564199831. Rain is one of the best archetypes in NatDex OU
2. There are a lot more Water type threats in the tier (like Mega-pert or Urshifu-R)
3. NatDex OU has banned the thing that keep her in check in regular OU like Kingambit, Dragapult, and Darkrai
4. Dondozo is a lot less effective in NatDex so it's seen far less often. This means that the set-up Ogerpon is really hard to check
5. Movepools are unnerfed in NatDex meaning Landorus-T remains the best Pokemon in the tier. She has a really good match up into him.