From MechWarrior: Living Legends Wiki
Chassis refers to one of two things.
- A chassis is one particular asset and all of its variants. For example: "The Osiris is a good "chassis" to mount DPS weapons that have a long stare time, this because it has a 360 degree torso twist."
- The chassis of each individual asset is its motile structure, its hull, legs, etc. with less emphasis on the torso or turret of the asset. For example: "Mechs need not rotate their entire "chassis" to spread damage, only their torso. Tanks, however, must rotate their entire "chassis" in order to do so."