Hi! Do I need a Visa to transit through China via Beijing and Chengdu to arrive finally in Nepal ?

I arrive to Beijing from Canada at 16:50 the 29th of March and I take a flight to Chengdu at 21:00 to arrive at Chengdu at 00:05 the 30th of March. I take my flight to Katmandu, Nepal at 8:35 the 30th of March.
I wil not have the nepalese visa on my passport, since they give it at the arrival in Kathmandu. Thank you !