After you say, "Hello, I'd like to welcome you to Malaysia," you could try one of the following conversation starters:
I hope you'll enjoy your visit to my country. / How long will you be visiting my country? / Is this your first visit to Malaysia? / What country are you from? / I know you've probably planned your trip, but if you have any questions about what places to visit, I'd be glad to suggest some. / Be sure to try some of our traditional foods, such as ____ , ____, and ______.