West Side, West
noun, の adjective
The West side of something is known as the West or the West side. Sorry, I have no story to go along with your West side.
にしがわ
The readings are the kun'yomi vocab readings. You should know both of them, with 西 being にし and 側 being がわ (what you learned with the kanji).
家の西側に黄色いものがあると金運がアップするそうです。
A house with yellow on the west side is said to bring good luck for money.
このホテルの西側には、大きなポプラの木が植えられていています。
A large poplar tree is planted on the west side of this hotel.
それって西側のメディアのニュースでしょ？
That's news from the western media, right?