Simplify the following text for a Grade 11 native English-speaking person.
Original: Chiasso ( , or commonly ( Ë kjaË so ) ; in Lombard : Ciass ( tÊ as ) ) is a municipality in the district of Mendrisio in the canton of Ticino in Switzerland .
Simplified: Chiasso is a municipality of the district of Mendrisio in the canton of Ticino in Switzerland .