How to get Typecho to fill in a nickname when registering

My website is built with Typecho, each time can find the user that column new registered users have so few login name is empty , preliminary inference is caused by special characters. Restricting special characters this is not difficult but since there is a nickname, that can be registered when you fill in the nickname, so that even if there are special characters can also display it?
So how can I get a nickname when the user registers?
Is it OK to add an input directly like a password?

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My website is built with Typecho, each time can find the user that column new registered users have so few login name is empty , preliminary inference is caused by special characters. Restricting special characters this is not difficult but since there is a nickname, that can be registered when you fill in the nickname, so that even if there are special characters can also display it?
So how can I get a nickname when the user registers?
Is it OK to add an input directly like a password?

Can be implemented you read the next registered PHP file to add a write nickname to the statement

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