I expect "support" to mean something different from Western devs and Japanese devs. Most Western devs are looking to port some of their old games over to Switch like Skyrim and LA Noire or maybe port some sports games over like FIFA. Expect to see this same kind of behavior from most Western devs for several years. Ports are better than nothing, but don't expect them to bring over their latest, greatest games until the end of the Switch's lifetime. (Ubisoft and Bethesda might get with the program before the others do though.)
Japanese devs are a whole other story though. The Switch will be the main handheld and home console in Japan for the next 5 years or so. That means almost every Japanese dev is making their best games for the Switch right now. If a Japanese game started development in 2017, then it will definitely be on the Switch. For games that started development earlier, they are going to be asking themselves if they can get the game ported to the Switch also.
We're only going to see a little glimmer of the full Japanese support in 2018, because games take time to make. Once 2019 hits, then expect Japan's best to start coming in a major way. Sequels to the biggest Japanese games like Nier or Persona or whatever other Japanese games you might be looking for are all going to be on the Switch when they finally hit. But I don't expect to see the full impact from Japanese third parties until 2019, because it is going to take them some time to adjust.