are metalloids amphoteric in nature

Metalloids are those elements which exhibit characteristics of both metals and non metals. They are solid but not lustrous and conduct heat and electricity moderately well.
There are six metalloids-  Boron, germanium, arsenic, antimony, polonium and tellurium.
Amphoteric are those chemical substance which can react with both acids and bases. And metalloids can react with both so they are amphoteric.
For example- reaction of boron with acid and base-
2B + 6NaOH → 2Na₃BO₃ + 3H₂
B + 3HNO₃ → H₃BO₃ + 3NO₂