Calculate combined standard deviation

If I have a data that I fit with NonlinearModelfit that fits a data based on two fitting parameters, c1 and c2.

When I used nlm["ParameterTable"] // Quiet I get the following table:


If I have an equation such as:

eq = (2.303*((70 + 273.15)^2)*(c1/c2))/1000

Is there any code (as opposed to doing it manually) I can use to calculate the value of eq with the combined standard deviation based on the standard deviations of c1 and c2 from the table?

Thank you!