So I found this in my waiting messages:

The caption explains itself. My boundless curiosity decided to check how legit this scam really was. I opened the link, and I was greeted with a phishing warning. I was like, "forget that," and looked inside.
Right off the bat I was greeted with this:

Official Steam links have a little green lock next to them, the "view aliases" button doesn't work, you can't block him or report him (how ironic) and clicking a certain hat links to this:

Yeesh, how the hell can anyone be able to fall for this? Anyhow, all the other links lead straight to the login page:

e did a r8 gud job der. And filling it out gives you this prompt:

Steam Guard sends you a code inside an email that you have to send to them. It's like all Russians look down on us filthy Americans and think we're so gullible.
Anyhow, if Nyanshka tries to add you, deny the request, report him, and block him.