Legal analysis: it is effective to write a nickname for debt. As long as the debtor approves, it is entirely possible. If the debtor refuses to admit that he signed the name, the creditor needs to provide evidence to prove that the name is the debtor's name and can apply for handwriting identification. IOUs need to meet the following conditions:

(1) The actor has corresponding capacity for civil conduct;

(2) the meaning is true;

(three) does not violate the mandatory provisions of laws and administrative regulations, and does not violate public order and good customs;

(4) borrowing.

Legal basis: Article 668 of the Civil Law of People's Republic of China (PRC) shall be in written form, unless otherwise agreed between natural persons. The contents of a loan contract generally include terms such as loan type, currency, purpose, amount, interest rate, term and repayment method.