Yes, rajgira chikki is generally acceptable in Jain diet for many people, because rajgira (amaranth) is commonly used in fasting and vrat foods.

But keep these points in mind:

• If you are observing a strict Jain upvas, then no solid food is taken, so chikki would not be allowed.
• If you are doing ekasana / beasana / vrat-style eating, rajgira chikki is usually considered acceptable.
• Make sure it does not contain any ingredients you avoid, such as:

- honey - root-based additives - non-Jain mixtures or flavorings

So, in short: yes, usually allowed — except during strict fasting.