We’re not strangers. VS We're no strangers.
Do they have the same meaning? Can I use both of them interchangeably in this context?

For example:
A: Thank you so much.
B: You don't have to thank me. We're no/not strangers.

Thank you in advance.

Question

We’re not strangers. VS We're no strangers.
Do they have the same meaning? Can I use both of them interchangeably in this context?

For example: 
A: Thank you so much.
B: You don't have to thank me. We're no/not strangers.

Thank you in advance.

Answer

In your example, I would say, "We're NOT strangers."

"no stranger"  is used in a different context.

She's no stranger to something = she's familiar with something, or she's had a lot of experience with something

She's no stranger to hard work (=this is something that she does all the time).

That TV show is no stranger to controversy. (=they have had their share of controversies over the years)

He's no stranger to conflict (= this is something that he deals with frequently)