Can I sue a guy for copying my video and claiming it as his own?

If you own the copyright of the video, you can file DMCA take down notice with Youtube. Log into your Youtube account, go to the video, click on the flag icon below the video, and follow the prompts to the DMCA Copyright take down. If you make a false claim, you can be sued. Can you sue the man for copyright infringement? Only if you have registered copyright with the US Copyright Office. Also, you will need to hire a lawyer to go into Copyright court, which may be quite expensive. Keep in mind, the 1.1 million views may be real, or may be paid-for fake views.

Anything put on YouTube, no matter how carefully copyrighted, is pretty much gone. You could sue the guy who took it but you'd have to prove that you didn't intend for anyone to copy it - which is pretty much the whole idea behind that YouTube. However, if you can prove that 1) you own the copyright to the original footage or that you created the footage and 2) the guy is falsely claiming it as his own in public, you have a case. Contact the owner of the service the guys site is located on and file a complaint first. They may help you get the footage taken down. If not, you'll have to turn to a court.

Yes. This is textbook copyright infringement.