I say "mostly" because the ability to re-download purchased software will remain up for the time being, but being able to buy anything on the eShop if you're located in Russia won't be possible anymore. Nintendo had already halted product shipments to the country around March of last year after the Ruble's value made a massive decline following the start of the war in Ukraine, so if anything it's a bit surprising they waited a whole year to mostly shut down the eShop in the country.
Aside: it's fucking weird to me I've seen vatniks try and claim Nintendo no longer doing direct business in Russia is somehow "virtue signaling." Dude it's because Russia's economy is a shitshow right now, simple as that.