I feed hornworms and black soldier fly larvae to a variety of things. Phoenix worms have a great calcium to phosphorus ratio and can be used as a staple diet for many herps. They're small though, so it would take a few of the largest size to fill up a tiger. Hornworms are expensive, but they're soft bodied and a good treat. There is nothing wrong with them, and are good in variation. They're usually fed to reptiles and are hard to resist because of their color and particular movement- I'm not sure how tigers would react to them. They can get very large and are little pus-bags, so you want to make sure you feed them off at the right size because cutting them will not be pretty.
Good luck to you. I'd try Phoenix worms first, then hornworms because of their price.