Manufacturers usually do not publish a specific “maximum lens weight” for DSLR bodies. In practice, there isn’t a commonly listed limit for normal use.

A lens around 1kg is generally not unusual, and bodies like the Nikon D3100 are expected to handle that safely in ordinary shooting. The bigger issue is handling technique: with heavier lenses, support the setup by the lens rather than letting all the load hang from the camera body. That’s good practice even with moderately heavy lenses.

As lenses get larger, many include a tripod collar; if a lens was sold without one, that’s a good sign it was intended to be mounted and hand-held normally from the camera mount. Very large telephotos are a different case and are typically supported by the lens itself.

So for a roughly 960g 80–200mm lens, the mount is very unlikely to be a problem. Just avoid carrying the camera by the body with a heavy lens swinging from it, and support the lens when shooting or transporting it.