Recent observations of very-high-energy (VHE, $\gtrsim 100$ GeV) afterglow emission from a few gamma-ray bursts (GRBs) raised important questions regarding the emission mechanism responsible for this radiation. So far, synchrotron-self-Compton (SSC) has been primarily used to model VHE emission from GRBs. As a first approach we have applied NAIMA, a publicly available code for radiation modelling from relativistic electrons, to model GRB afterglow emission. We present predictions of multiwavelength energy spectra for GRB~190829A, assuming the emission is SSC in a wind scenario. In our prior work, using a code developed by us, the SSC model gave a satisfactory fit to the VHE data for a given set of fixed model parameters for this particular GRB, with a wind environment preferred over a constant density inter-stellar medium. NAIMA already includes optimisation tools to perform Markov Chain Monte Carlo (MCMC) fitting of radiative models to multiwavelength spectra. This is our motivation for this study of comparing optimised model parameters from NAIMA to those from our own code. Finding a more robust fit of the model to the observations has implications on future observations, especially by the CTA Observatory, implying better constraints on the GRB environment and the particle energy requirements for the emission observed at late times.