Lack of interest Weird usernames/spam/registration

[ŽivaAkcija]

Any chance to Xenforo add option over registration to user use only one big letter and max two numbers in their nick names, when i run my forum i got realy big issue with usernames spok234545, drew23js44 and similiar

 

[Fred.]

I think you might be able to prevent this with a regular expression. But you have to ask a pro for the regular expression because I don't understand them.