なさる
なさる · nasaru · JLPT N4 · verb-godan
-- honorific expression for する --
なさる = polite なす (to do) — the respectful stand-in for する
なさる is the honorific form of the old verb なす (to do, to accomplish), so it replaces する when someone you respect is the doer. It is also the source of the polite command ending なさい, as in 食べなさい.