hello regarding end of service for nannies

The UAE Domestic Workers Law grants the worker the right to obtain the end of service gratuity, which is the reward that is calculated at the rate of fourteen days' wages for each year of service. If the employer refuses to pay the value of that bonus, then you can file a complaint with the Ministry of Human Resources and Emiratisation.
Here is a text of the law on domestic workers related to your inquiry:
Article (26)
1. A worker who has completed a year or more in continuous service shall be entitled to an end-of-service gratuity at the end of his service, and uninterrupted work days without remuneration will be included in the calculation of the service period and the reward is calculated on the basis of fourteen days' wages for the year, provided that the worker receives his dues from the end of service gratuity at the end of the contract, and the reward account is renewed by renewing the contract.
2. The worker deserves a reward for the fractions of the last year in proportion to what he spent on the job, provided that he has completed a year of continuous service.