multivariate nonlinear regression problem

Now I want to solve a multivariable (x=13) and multivariate (y=84) nonlinear regression problem. When using Maschine Learning Toolbox, I have found that I can only choose one response for the problem. Could anyone recommand me a good solution by using the Maschine Learning Toolbox? (I know I can use neutral Network, but the company has not this Toolbox.) I have also tried Function-mvregress, but it seems not work well because the problem is not a linear model. Thank you very much in advance.

[Sachin Meena]

Hey Zhenchen, have you tried out this solution ?

[Zhenchen Fan]

not yet, could you help me