I have been in the US with my F1 student visa for over 6 years. Should I file tax as a US resident (i.e. with Form 1040, instead of 1040NR)?

Thank you very much!

Yes, file resident return. Your U.S. Tax Return: The U.S. Visas

So, does it mean that I am eligible for the $400 "Making work pay credit"?

Thank you.