I don’t think there is a reverse direction for /streams. You’ll probably have to use ._total for &offset= and &limit= parameters.
/streams?sort=views&language=en&game=overwatch&limit=1
{ _total: 915, streams: [ {} ] }
Get all, in reverse chunks
You could use floor(_total / 100) * 100 to get the start offset for reverse sorting and use as many request as you need. You’ll still need to reverse the streams array data.
/streams?sort=views&language=en&game=overwatch&offset=900&limit=100 // 15 items
/streams?sort=views&language=en&game=overwatch&offset=800&limit=100 // 100 items
....
/streams?sort=views&language=en&game=overwatch&offset=100&limit=100 // 100 items
/streams?sort=views&language=en&game=overwatch&offset=0&limit=100 // 100 items
Get the last 100
Or just subtract 100 from _total and then go from there if you just want the last 100. Again, make sure to reverse the streams array data or at least recognize that it’s still descending order.
/streams?sort=views&language=en&game=overwatch&offset=815&limit=100 // 100 items