$900 Usd Gaming/Streaming Pc

Hi, I'm posting this for my brother hes looking for a Gaming/Pc Gaming computer so he can stream games. Catch is that he only has a $900 Usd budget so that might limit some things. I need a full computer build. Hes looking to buy this coming week. Thanks in advance.

Budget: $900 Usd

Where do you live?: United States, Nashville Tennessee, Currency is the USD

Retailer I prefer: None, Just the cheapest and most reliable, I do not have a MicroCenter where I reside.

Pc Peripherals Needed: Monitor 1080p.

Pc Use: Game Streaming.

Overclocking?: Maybe in the future.

Custom Water Loop: Probably not.

Is a new OS needed for this build: Yes, a new OS is needed one best for gaming.

Game Settings: Highest Setting for my price at 1080p at a respectable FPS.

Game Resolution: 1920x1080 This is fine for now.

Games likely to be played: Mobas and Rts.

Main game being played: League of Legends.

Storage: A good sized SSD and at least a TB for the mechanical HHD.