expression
no problem; nothing to worry about
Jocular, humorous phrase playing on 問題なし (no problem) by replacing なし with the English word 'nothing' written in katakana. Used in casual, playful contexts.
「遅刻しちゃったけど大丈夫？」「問題ナッシング！」
"I'm late, but is it okay?" "No problem!"
このくらいのミスなら問題ナッシングだよ。
A mistake like this is nothing to worry about.