Guangzhou Baiyun International Airport CAN transit visa requirement

I am a Nepali citizen traveling from Canada to Nepal by China Southern Airlines. Do I need transit visa?
Please suggest me if I need a transit visa in any case of my travel. My main concern is Guangzhou Baiyun International Airport CAN.

Below is the detail of my layover in China:

11:40
Vancouver International Airport YVR
Travel time: 13 h 40 m
17:20+1
Guangzhou Baiyun International Airport CAN
China Southern
Economy
Boeing 787
CZ 330

14 h 55 m layover

Guangzhou CAN
Overnight layover
08:15+2
Guangzhou Baiyun International Airport CAN
Travel time: 5 h 25 m
11:25+2
Tribhuvan International Airport KTM