Return ticket to Santiago

hola a todos
i am a greek who wants to travel to chile next month and i have a question with my return ticket.Do i have a problem if my return ticket it will be more than 3 months(looking for 6 months return ticket);If the airline company let me to get on board?Am gonna travel after that in Argentina and peru and at the end i will return from Santiago to Greece.
i know that the passport stamp it will be for 90 days with the right to renew with more 90  days if i ll go to extrangeria office or to do the "mendoza run".

This is not a problem as long as you have a return ticket. Have always booked flights for 8-9 months in advanced when I have traveled to Chile.