Google Sheets will automatically update charts with new data as long as it's in the selected data range. It's also possible to combo it by making a spreadsheet automatically from the Forms thing, so one could just punch in the numbers into the form and it'll automatically spit the data out into the sheet which will automatically update the chart for that data.
For example, here's a form I made in about 13 seconds,
And here's the spreadsheet,
The chart was actually made after the second "response", but I haven't had to touch it since. I simply punched in some random numbers and the chart updated after a couple seconds. Try it out if you want.