If you're talking just eShop, then yeah. There's occasionally some flukes, like Link's Awakening being $40 right now, and you can find sales on stuff like the Xenoblade and Fire Emblem series from time to time, but for the most part they stick to MSRP for their major IPs. I can't remember having ever seen a sale on any Nintendo DLC either... about to finally just give up and buy the FE3H Expansion Pass at full price because a sale is never going to happen. Only way you're getting a discount on that sort of thing is by finding eShop gift cards on sale.
Other stores can sell digital codes though, and they'll have deals on stuff Nintendo never really discounts (like Mario stuff, BotW, etc.).
Digital is pointless for the Switch anyway though. Carts are superior in every way besides the minor annoyance of having to carry and swap them if you play more than one game at a time. They load faster than a SD card and you don't have to worry about running out of space, they go on sale much more often, you can trade them in if you want, Nintendo's network downloads ungodly slow over wireless and it's still not great even if you get so fed up with it that you buy a USB ethernet adapter for the damn thing.