This seems to be a combination of "folk dance" to celebrate the Glories of Lord KRshNa. Culture, tradition dovetailed to [VishNu-]bhakti (devotion to Lord VishNu).
The bhajan singer / narrators say -- "KRshNa leelA bhajo mani" -- Meditate on the glories of Shri KRshNa in your mind. Chant His names -- there is an intermittent cheer of "Hari bol!" "Hari bol Hari bol Hari Bol!"
The dancers (folk local style) -- are the common man celebrating the glories of Shri KRshNa -- because when Lord KRshNa Who is pure Truth and Ananda (happiness) personified, manifests in their heart, the heart is bound to rejoice.
"The Gopis were 16 and KrshNa was 12 (solah sAle gopi nile KRshNa-jilay barah)" They said His melodious transcendental flute notes made them forget the world. Seeing KRshNa's Lotus-like moon-like face made them very glad.
Then another singer explains --- when Radha is not around KRshNa's heart goes "Radhe Radhe" and when She is, He teases Her.
KRshNa brings peace, solace, fearlessness and devotional surrender in the hearts of devotees who are represented here by the "Gopis" Gopis are not girls or women, but pure souls, jIva devoted to the Supreme Lord, paramAtmA.
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You will find Bhagvat katha discourses, worship of the same deva devatA (Gods, Goddesses) the same sects and subsects in Nepal. The regional folk tradition is a medium of expressing the glories and stories of Ramayana and Mahabharata.
The only difference I can think of is their blending with Buddhism, and a lot of intermingling of Hindu and Buddhist temples. After all, Bauddha Dharma grew as an offshoot from Hindu Dharma. Also, there will be some differences in local beliefs and worship.
Disclaimer : This is intuitive observation to the extent paramAtmA -- Lord of the heart -- provides. I do not know any Nepalese personally.