Which of the point mutations is considered most harmful

Between silent mutations, nonsense mutations, and missense mutations.

Thanks so much!

Silent mutations are the least harmful because the same polypeptide chain is formed due to the degeneracy of the genetic code.
Nonsense mutations are the most harmful because they result in premature termination of translation as the codon coding for an amino acid is replaced by a stop codon. This results in a non-functional truncated protein.
Missense mutation can also be pretty harmful, sometimes altering the action of a protein and sometimes forming a non-functional protein. That's why it's a little hard to compare a missense and a nonsense mutation at times.