。
That last one didn't count, OK?
Literal
Now [attributive-の] [nominalizer-は] no-count is-[because-から][confirmation-ね].
Casual game/contest speech. 今の is the pronominal の standing in for 'the one just now, that last thing.' ノーカン is slangy wasei-eigo from 'no count,' used in games and sports to declare an attempt invalid/doesn't count — 'do-over!' or 'that one didn't count.' ~からね is the casual reason-marker with ね inviting agreement.