Don’t start chat on baby's toy (6)
I believe the answer is:
rattle
'baby's toy' is the definition.
(I've seen this before)
'don't start chat on' is the wordplay.
I cannot really see how this works, but
'on' could be 'at' (I've seen this in other clues) and 'at' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for rattle that I've seen before include "Baby's toy; irritate" , "Make someone nervous or anxious" , "Venomous creature's warning" , "Gurgling sound in throat" , "Disconcert - conductor, Simon" .)