She might be initially shocked. Given her own past traumas and her relationship with Naruto, she could be hesitant at first. But then, considering Naruto's lonely situation, she might warm up to the idea and show a more maternal side towards him.
Naruto might be longing for a motherly figure in his life. He has always been alone and has seen how others have mothers. Tsunade, being a strong and caring woman in the village, could be someone he looks up to and wishes to have as a mother.
Naruto might be initially confused. He trusts Tsunade, so being kidnapped by her would be completely unexpected. He would probably start by asking her why she's doing this.
One possible reason could be extreme guilt. Maybe Naruto has done something he believes is unforgivable, like accidentally causing the death of a beloved friend while in a fight. He might think that death is the only way to atone for his mistake.
Tsunade could be a bit flustered at first. After all, she is a tough - as - nails leader, and a hug from Naruto, who she has watched grow up, might make her feel a bit vulnerable in a good way. She might then relax and even give Naruto a pat on the back in return, showing her appreciation for the gesture.
Tsunade would probably be very suspicious at first. Naruto suddenly appearing from the future? It's not something that happens every day. She might think it's some kind of enemy's trick or a genjutsu.
At first, Naruto might be extremely shocked. He has always seen Tsunade as a respected figure. So when she hurts him, he may not be able to immediately process it. He could be speechless and just stare at her in disbelief.
He would probably also feel angry. After all, he has sacrificed so much for the village and for them. He might start to question his own beliefs and values. But Naruto being Naruto, he would not give up easily. He would try to prove his innocence and show them that they are wrong. He could go on a journey to find evidence or seek help from other allies who still believe in him, like Shikamaru or Kakashi.
Tsunade would probably be shocked at first. Naruto is like family to her. She might immediately refuse and try to talk some sense into him. She could say something like 'Naruto, you're stronger than this. There's always a solution to every problem.'
Well, it depends on the specific fanfic. There are a lot of fanfictions out there with different takes on the Naruto universe. Some might make Tsunade Naruto's grandmother to add a new layer of family - related drama or to explore the idea of how her leadership and medical skills could be related to Naruto in a more family - centric way. It can be a really creative way to re - imagine the relationships in the Naruto world.
Naruto would be deeply hurt. He would probably feel a mix of anger and sadness. At first, he might try to reason with Tsunade, to find out why she betrayed him.