Automate Helm's tiller installation with Terraform
How I see there is two options (from my exp):


Use configuration for provider. 
https://www.terraform.io/docs/providers/helm/index.html, there is option to install tiller.
Use prefabricated modules, for example:
https://github.com/sagikazarmark/terraform-tiller
https://registry.terraform.io/modules/Vidimensional/tiller/kubernetes/0.0.1