This is quite the confusing question. That is the default touchwiz phone or dialer. It's called "Phone" on mine and it's in my App Drawer. If you're using a different icon pack in Nova it might not be a green phone icon.
This. Nova is probably just showing you a different phone icon. I'm not familiar with Nova, but some launchers allow you to customize icons. Maybe you can simply use the green (original) phone image as your Nova phone icon?
I use Nova Prime and have not loaded up any icon packs, so the stock icons show. My phone dialer looks precisely like yours (edit to clarify, it looks like your screenshot above).
Go into the app drawer (the six dots in a circle) and look alphabetically for an app called "Phone". If the icon for "Phone" is different, you've probably selected Lollipop or KitKat icons. Launch the app called "Nova Settings", then go into "Look and Feel", "Icon Theme" and set it to "System" and it will use the icons provided by the system libraries themselves.
I really think we're being trolled. No way does a person who's able to install and configure a 3rd party launcher and take and post a screenshot of their home page all of a sudden not understand what the "Phone" icon is or where it's located.
He or she probably just missed the setting in nova, as stated above...there are a lot of settings and if it's their first launcher replacement there is a learning curve...To the op good luck and I'm sure you will find what you like.