Question about TD-visa holders

I am a Chinese Canadian that works in the U.S. as a TN-visa holder, my wife holds a TD-visa.
To kill some time, my wife is considering doing some independent contractor (or self employment) work, such as opening a small business or doing some online survey to earn some pocket money.

Does anyone know if this is legitimate? I know TD-visa holders cannot work in the U.S., does this restriction also apply to our plan stated above?

Any advice will be highly appreciated. Thank you very much.
Sorry I cannot type Chinese.