I have Al bicrsytal with Ni atoms segregated at grain bounday. I wish to get a plot of Ni concentration vs distance. I am attaching a figure as a reference ,what I intend to do.
I want to know that is it possible to do it with ovito or ehat is the right way to calculate this.

You could define a group for the Ni atoms and then use that group with compute chunk/atom and ave/chunk to get the number or mass density as a function of distance. That would be for the line plot. For the Ovito plot, you could just use a picture of your model with respect to the appropriate viewport (with the appropriate atom colors). You could also use the color coding modification with particle type as the input property.

Best Regards,