なりとも・たりとも～ない: the difference
なりともN1
Meaning
Even
Past papers
Example
一言なりとも、あなたの気持ちを聞かせてくれませんか。
Wouldn’t you let me hear at least a word about how you feel?
たりとも～ないN1
Meaning
Not even one, Not a single, No
Past papers
Example
人間は酸素なしには１日たりとも生きられない。
Humans can not live even one day without oxygen.
How to tell them apart
「なりとも」: followed by a positive wish or request ('even a little, please let me ...'); very refined.
「でも」: modern everyday style, plain, as in 「お茶でも飲もう」.
「〜たりとも〜ない」: must be followed by a flat negative ('not even a bit'); it cannot make a request.