The link on the Doodle takes one to a list of Teacher’s Day related links which explains Nepal’s teacher’s day,  also known 'Ashad sukla purnima’.

“Teacher's day is called "Guru Purnima" in Nepali, where "Guru" means teacher and "Purnima" means "Full Moon". Celebrating "Guru Purnima" is a very old tradition and it is related to ancient Hindu tradition. Among Hindus, the person who teaches "Mantras" during "Bratabandh ceremony" is considered as the real "Guru", reads the Wikipedia description.

Also, check out this video uploaded by Google Doodle on Youtube. 

Doodles are surprising and spontaneous changes that are made to the Google logo to celebrate holidays, anniversaries, and the lives of famous artists, pioneers, and scientists. A team of illustrators—who are called doodlers—and engineers are behind each doodle.

Earlier, on the occasion of Nepal’s republic day, Google has dedicated a doodle to honour, the resilience of the Nepalese people. Google created this ‘doodle’ to honour Nepal’s Republic Day. “Today, we honour the strength and resilience of the people of Nepal,” Google wrote in a message in May.