Is Google Chrome's Incognito Mode an isolated session (it's a fresh browser window with all the default settings applied, and is it possible for your employer to monitor your Incognito activity on your home computer if you're signed in with your G Suite Google Account?
Let me divide your quesiton in parts:
When you start a new incognito mode you get a brand new session (shared across incognito windows) this is by design. Let's say you want to open a new Facebook account other than your own, you can only open one in Incognito, this is by design. Imagine the pain as you're browsing incognito if every time you open a new link on a website you have to log in. What happens with the profile when you close it? It gets wiped, nothing ever gets stored from it.
About your employer... If you're at work, they have other ways to monitor your computer, there's applications to monitor computer usage, capture keyboard, screen, sessions, cookies, etc. (It's always good to share a reminder)
Regarding your Gsuite, when you're incognito you can not attach your profile with your Gsuite account, so I'm guessing you're just logging on the website. They can only do tracking within that website and other websites that track with Google. I'd say you're safe, but if you're using your GSuite account as a personal, I'd strongly suggest against it. In chrome you can have more than one profile.
Lastly, I never mix home with work. Most of my work stuff from home gets done on a VM with a nat network. Isolation is best.
Sort of yes and no it is a fresh browser window with its own set of settings if you use it frequently you can change things and have them stick across sessions what incognito does not do is log your activity in your own history it does not keep cookies or temporary files. Incognito can still be monitored for activity as it is used however not a truly anonymous browsing session.
As for if your boss can see your home computer activity really depends on his monitoring method and if your g suite is part of your work if you had to submit social media handles and such so they could watch those accounts. If the "home" computer is a work issued computer there is a possibility he can see if there is monitoring software on it. If the pc is personal and you sign into google services aside from if the files you access are part of the business then no he likely can't see your activity.