Nepal has significant populations of Tigers Leopards and Snow Leopards. Historical knowledge would state that tigers rule on the countries southern plains, Leopards rule in the mid country hill region and Snow leopards in the Himalayas.
Global warming is changing that fast, and it may cause the loss of species adapted to life in cold regions. In recent years, Tigers and Leopards have both been seen above 3000m though conservationists suggest that Tigers are generally unlikely to stay so high for long. Across the border in India and Bhutan Tigers have been photographed as high as 4000m high, and given that Snow Leopards are thought to live between 3000m and 5000n there is an easy case to be made that tigers will take over all of the snow leopards remaining territory.
Down in the lower plains, tigers tend to displace leopards. At height it is unlikely that there is enough prey to support a second large feline carnivore.
Current thinking is that these tigers encountered at extreme height are recently separated from their mothers and looking for territory- they are generally transient, and while some breeding behaviour has been noted at time this is rare. There is likely more threat from leopards than tigers, though at the current time, this is also thought to be a low risk.