Are there nonstop flights from Sapporo (CTS) to Chiang Mai (CNX)?

Yes. Thai AirAsia fly this route. Flight time is about 6h 9m.

What is the fastest connection from Sapporo (CTS) to Chiang Mai (CNX)?

via Seoul ≈ 6h 39m, via Busan ≈ 6h 43m, via Shanghai ≈ 6h 43m (estimated flying time, excluding layovers).

from 19,000 ANA miles, from 23,000 JAL miles (economy, one way, based on the published award charts).

New Chitose Airport (CTS) to Chiang Mai International Airport (CNX)・4,803 km

Nonstop flights available (1 airline). Flight time about 6h 9m. Nonstop return flights also operate.

With milesANA 19,000 miles+ (via TPE)JAL 23,000 miles+ (via ICN)Economy, one way, estimate. Tap a connection for miles by cabin.

10 one-stop options, sorted by estimated flying time. Tap one to see the airlines on each leg and booking links.

Times are estimated from distance. Check schedules, frequency and availability with the airline or a booking site.