Wow, I can't believe it, this is a new era for Nintendo, truly Region free!
I just tested it and my Singapore Credit card works on the Japanese app store. Some Japanese games like Disgaea 5 have complete english support and you can buy the games directly from any region's store you want with any credit card (Up to you to calculate which ones are the cheapest)
All you need to do is to create a Japanese nintendo account, no need for address or anything. Just need a unique email.
You can easily check which games have full english support : Head to
https://www.nintendo.co.jp/software/switch/index.html, it consists of all the games that are released on jp eshop.
Click on any game that fancy you, and within its page look for 対応言語. There you will see which language the game supports. 日本語 = Japanese, 英語 = English.
You can play the game with any nintendo account created on the system. Happy gaming guys!