1.16 20w16a - Checking custom tag on block under player

Hello!

I've once again gone looking for the answer, but not finding it on my own through resources or testing.

I'm trying to test for a block under any player that has a custom name or NBT tag associated with it.

In my testing, I'm just trying to turn a stone block into a spawner, but only if it has a custom name or tag associated with it.

/execute as @a at @s if block ~ ~-0.3 ~ minecraft:stone run setblock ~ ~-1 ~ minecraft:spawner

This command works fine on normal stone , but I've like to be able to add arguments to the stone such as:

/execute as @a at @s if block ~ ~-0.3 ~ minecraft:stone[nbt={MobSpawner:1b}] run setblock ~ ~-1 ~ minecraft:spawner

My current give command:

/give @p minecraft:stone{MobSpawner:1b} 1

I'm also open to other ways of achieving similar results! Any help would be appreciated.