Let's just say, this will chip fast for a couple of reasons
1) You didn't apply enough layers
2) You applied the paint over the chrome without sanding it
3) You didn't use high durability spray paint (plasti-dip won't last long)
I've personally used high thermal matte black paint that is used to paint headers (ultra durable, I've tried a bunch of them)
I sanded the chrome parts prior to applying the coats
I applied like bajillion coats
It all lasted me about 20k miles, which isn't bad at all, considering that 90% of my driving is on highway with speeds over 70 mph. Only recently it started chipping a little bit.