I am confused and overwhelmed!

I brought home an 8 weeks old puppy (Havanese) a week ago. First thing first, Is this normal for the puppy to be biting and nippy all the time? I mean ALL THE TIME? Unless he is playing or eating or sleeping, he is biting something. My hands, feet, clothing, baseboards you name it. I try to redirect him to his chew toys but this constant biting is making me crazy. I know puppy will nip and bite but really that much? How was your experience? He nap regularly as well.

And I cannot teach him anything at all. I’m only trying to teach him his name and “Sit” but he is so distracted even when there is just him and me in quiet place. When I teach him to sit, he would rather jump up to my hand to nip. Sometimes he is not even interested in the treats as well (they are high value treats and he seems to like it). He just wants to play and nip all the time so I cannot teach him anything. I am worried and I need some help.