Yes, nonuplicate and decuplicate come after octuplicate. Octuplicate refers to something that has been multiplied by eight, while nonuplicate refers to something that has been multiplied by nine, and decuplicate refers to something that has been multiplied by ten. So, the order would be octuplicate, nonuplicate, and then decuplicate.
quintuplicate sextuplicate septuplicate octuplicate nonuplicate decuplicate
undecuplicate, dodecuplicate, tridecuplicate...
quintuplicate sextuplicate septuplicate octuplicate nonuplicate decuplicate