Typing /kill @e[nbt={Powered:0}]
does not do antyhing. This command should kill all the creepers who are not charged.
MC-248511
Unable to filter charged/normal creepers using commands
Resolved
Invalid
0
(Unassigned)
Unconfirmed
(Unassigned)
command, command-bug, commands
1.18.1, 22w05a
Retrieved
The NBT key has no capitals (so "powered")
The NBT is a byte (so 0b/1b, not 0/1, those will never succeed in tests unless the NBT is an int.)
See MC-87252. Use nbt=!{powered:1b} to target uncharged ones as the tag is optional and will not exist if the default value (0b) is used, as such testing for it being 0b won't succeed.