TN works for Canadian company on the side?

Hi,

I currently work in US and plan to claim non-resident status this year. However, there's a small Canadian company wants me to do some small projects for them. So I have two questions:

1. Is this ok/legal for a TN worker?
2. How would this impact my Canadian tax return? Can I still be a non-resident and just file income tax for the small amount of cash I would get from that company?

Thanks a lot!