https://www.thesikhencyclopedia.com/biographical/hindu-bhagats-and-poets-and-punjabi-officials/devi-das-pandit/
Pandit devi das was a court poet of Guru Gobind Singh ji.
There is a manuscript of Hanuman natak of 1824 AD at panjab university, chandigarh written by ratan Singh Bhangu, the famous author of panth parkash.
In this manuscript, Ratan Singh Bhangu writes that his elder brother learnt Hanuman Natak from a person named panjaba.
Panjaba learnt Hanuman Natak from kavi Sainapati and Sainapati ji learnt it from pandit devi das.
This proves that Hanuman Natak was taught in Guru Sahib's Darbaar.