Pros:
Sludge Bomb hits Tapu Fini SE as well as other fairies like Clefairy.
Earth Power takes care of Regieleki, Coalossal, Metagross and Incineroar.
Great coverage, with Ice Beam, Thunderbolt and Flamethrower.
Good bulk on Nidoqueen.
Great ability with Sheer Force combined with many special moves with additional effects.
Cons:
Average speed and special attack.
Nidoking is frail.
Nidoqueen has even lower speed and sp.atk, although it can be made up for with high powered moves.
Bad matchup against the meta in terms of weaknesses. Glastrier destroys it when Trick Room gets set up, Calm Mind Tapu Fini can deal high damage, as can Specs. Dynamaxing Landorus-T that's faster can also destroy it although Adamant variants can be outsped by timid Nidoking and Ice Beam does a lot.
They could be OK, but I would say Nidoqueen over Nidoking if you want a Pokemon that lasts longer but Nidoking could be used if you just want a frailer, faster and slightly stronger Pokemon.
Partners:
It appreciates Tailwind with its average speed, so Tornadus-I is a good ally, as is Whimsicott. Incineroar support could be useful for Intimidate support. G-Moltres seems good as a dynamax ally, since the Nidos cover its weakness with their STABs, and G-Moltres's STAB Dynamax moves lower the opponent's special defence and raise your speed, both of which the Nidos highly benefit from.
So I would say OK. Bad weakness, support needed, but good offensively.
Hope I helped!
