Come to think of it, you're right — Tanaka-san never took a single hit in the mock battle.

Literal

Indeed, being-told-[conditional-てみれば] certainly, Tanaka-san [topic-は] mock-battle [in-で] once [even-も] hit-received not-was [confirmation-ましたね].

なるほど 'I see, indeed.' 言われてみれば 'now that you mention it / come to think of it' — literally 'if I try being told.' 模擬戦 'mock battle, war game.' 一度も…ない 'not even once.' The speaker is processing a realization prompted by someone else's observation.