Typo:

 IF ($1 == nm) { say 4 4N12ever 4N12ind 4 $2- | HALT } 

Should say

 IF ($1 == nm) { say 4 4N12ever 4M12ind 4 $2- | HALT } 

And you need a closing bracket at the end of the snippet

  on 1:input:*:{

  IF ($1 == lol) { /say 4,1 4,1L12aughing 4,1O12ut 4,1L12oud 4,1 $2- | HALT }
  IF ($1 == wb) { say 4,1 4,1W12elcome 4,1B12ack 4,1 $2- | HALT }
  IF ($1 == ty) { say 4,1 4T12hank 4Y12ou 4 $2- | HALT }
  IF ($1 == np) { say 4,1 4N12o 4P12roblem 4 $2- | HALT }
  IF ($1 == lmao) { say 4,1 4L12aughing 4M12y 4A12ss 4O12ff 4,1 $2- | HALT }
  IF ($1 == afk) { say 4,1 4A12way 4F12rom 4K12eyboard 4,1 $2-  | HALT }
  IF ($1 == nm) { say 4 4N12ever 4N12ind 4 $2- | HALT }
  IF ($1 == wtf) { say 4,1 4,1W14,1hat 4,1T14,1he 4,1F14,1uck 4,1 $2- | HALT } 
  IF ($1 == omg) { say 4 4O 4M12y 4G12od 4 $2- | HALT }
  IF ($1 == stfu) { say 4,1 4S12hut 4D 4F12uck  4U12p 4  $2- | HALT }
  IF ($1 == brb) { say 4,1 4B12e 4R12ight 4B12ack 4 $2- | HALT }
}