During the First Opium War the Chinese weren't really aware that the British in India and the British in Guangzhou were the same.
What if they were aware, and with a much more warlike government, the Qing decided to take the First Opium War west? After all, Nepal actually suggested an anti-British alliance only a few years after, so perhaps Nepal could be encouraged to join. Perhaps even the Sikhs and/or the Burmese. There's even a possibility of an earlier Sepoy mutiny.
What would be the most likely consequences?