This information comes from Nintendo president Tatsumi Kimishima:
"Nintendo Switch has not been on the market for long, but we already have a lot of software publishers who see Nintendo Switch as an opportunity to expand their business moving forward. More than 300 software publishers at present, including indie developers, have begun developing game titles.
This is just some of the lineup that has been announced. As you can see, the wide variety of genres among the titles will further increase interest for Nintendo Switch. Having a broader consumer base will make it even easier for software publishers to do business. We are also continuing our work to establish a collaborative framework that facilitates the creation of more successful titles for our software publisher partners."