Make sure your table selection includes tblSystemEnclosure and TsysChassisTypes.
Linkage:
tblAssets -> tblSystemEnclosure -> TsysChassisTypes
Inner Join tblSystemEnclosure On tblAssets.AssetID = tblSystemEnclosure.AssetID
Inner Join TsysChassisTypes On TsysChassisTypes.Chassistype = tblSystemEnclosure.ChassisTypes
Once you've got that, the description of the chassis is
TsysChassisTypes.ChassisName.