What is the purpose of the oversize beak found on toucans?

Overall the toucans be it's multifunctional adaptation that enhances its survival and reproductive success in its natural habitat

While it is used to help it get food (as is common for most birds), the distinctive feature of the toucan's large (and remarkably light) beak is to act as a thermo-regulator. This means the toucan can dissipate excess heat by increasing the blood flow through the beak, whose large surface area allows for effective heat transfer to the surrounding air.

https://www.science.org/doi/10.1126/science.1175553