Ever since the Switch was announced, there have been rumors swirling that Blizzard would get back on the Nintendo horse, something they haven't done in ages (Starcraft 64 anyone?). But it appears as if those rumors are dead, at least according to one developer. Designer Dean Ayala confirmed to PowerUp Gaming that as of 2018, "there are no plans to move Hearthstone to the Nintendo Switch."
Blizzard Entertainment's relationship with non-PC platforms is fascinating. They originaly got their start (under the guise of their original name, Silicon & Synapse) on consoles, spliting their duties between the SNES and Genesis. Then when Warcraft came along they kind of abandoned everything but PC, coasting all the way into Diablo, which took a brief detour with a PlayStation version.
Then Blizzard produced their only Nintendo platform project to date, Starcraft 64, and stopped working on anything console related for a decade. Diablo III and Overwatch followed as console releases in 2013 and 2016 respectively, but there hasn't been a Nintendo console release in nearly two decades. We don't know if there's a hard stance against it, but given the Switch's uptick and the fact that it could clearly host Hearthstone (and likely Diablo III and its next potential expansion for that matter), the whole situation probably deserves a re-evaluation.
Cross-play is currently a thing for PC, mobile, and Switch users in Minecraft -- imagine that functionality in Hearthstone and the benefits of the increased playerbase.
Blizzard: “There are no plans to move HearthStone to the Nintendo Switch” [PowerUp Gaming]
via destructoid https://www.destructoid.com/even-though-it-would-be-perfect-for-it-blizzard-still-has-no-plans-for-hearthstone-on-switch-487863.phtml