References for Each Chapter for Dissertation writing in Overleaf

Question

I am writing my dissertation and am following the format of this link: https://github.com/UA-ACM-Student-Chapter/uathesis. However, the author of this document has only one big reference added at the end of the dissertation. I am trying to create separate references at the end of each chapter, and I am following the technique described below:

My code in the main text:

\documentclass[dissertation]{uathesis}
%% Basic packages you'll probably want to use.
\usepackage{graphicx}                 %% For using \includegraphics{}
\usepackage{color}                    %% For colors used in listings.
\usepackage{listings}                 %% Code listings (for engineers)
\usepackage{csquotes}
\usepackage{notoccite}
% with this command, you can add a kerning to all possible math quotations and of course change or delete them later, if you change the font or dislike your first chose.
\usepackage{hyperref}
\newcommand{\mathenquote}[1]{\enquote{$#1$\kern.3ex}}
\usepackage{xfrac}
\usepackage{comment}
\usepackage{color,soul}
\usepackage{float}
\usepackage{booktabs}
\usepackage{graphicx}
\usepackage{array, multirow}
\usepackage{setspace}
\usepackage{adjustbox}
\usepackage{tabularray}
\usepackage{caption}
\usepackage{subcaption}
\usepackage[numbers,sort&compress]{natbib}

\usepackage[sectionbib]{chapterbib}

\usepackage[titletoc]{appendix}
%% Required parameters (these default to undefined)
\author{Nisha}       %% Your name!
\adviser{Dr.}   %% Your adviser/committee chair!
%% The people on your committee.
%% Use \and to break them up between lines.
\committee{
  Dr. K \and
  Dr. M \and
  Dr. J \and
  Dr. D
}
\title{Con}
\degree{Doctor of Philosophy}   %% Change to suit your degree.
\department{Elec Engineering}   %% Change to suit your department.
%% These are body text paragraphs to be placed in the front matter.
%\abstract{
  %There is such a thing as \gls{tmi}. My brother once said that \gls{tmi}
  %is what drives the world, some times causing fits of \gls{lol}. If one
  %is to get in a especially deep fit of the \glspl{lol}, then one could
  %find oneself \gls{rotflol}.
%By the way, \gls{alpha} and \gls{beta} are Greek letters.
%}
%\dedication{
  %Type or input{} your dedication here.
%}
%\acknowledgments{
  %Type or input{} your acknowledgments here.
%}
%% Optional parameters. The default usage is shown.
\university{The University of Alabama}
\school{Graduate School}
\gradyear{\the\year}
\place{Tuscaloosa, Alabama}
\begin{document}
%% Makes the title, abstract, dedication, table of contents, etc.
%% Must be before \begin{body}
\makefrontmatter
%% BODY PORTION
%% The bulk of your thesis.
%% Begin your \chapter's here.
\begin{body}
%\mainmatter
\include{chapter/chapter1}
\include{chapter/chapter2}
\include{chapter/chapter3}
\begin{appendices}
\addtocontents{toc}{\setlength{\cftchapnumwidth}{1em}}
\renewcommand{\appendixname}{APPENDIX}
\addtocontents{toc}{\setcounter{tocdepth}{0}}
\addtocontents{toc}{\protect\renewcommand{\protect\cftchappresnum}{}}
\chapter{A BIG APPENDIX}
\end{appendices}
\end{body}
\end{document}

chapter1.tex:

\chapter
This chapter
\section
This section. \cite{walis08,thomas09}
\renewcommand{\bibsection}{\topskip=1in\chapter*{REFERENCES}\topskip=0in \addcontentsline{toc}{chapter}{REFERENCES}}
\bibliographystyle{unsrtnat}
\bibliography{literature}

chapter2.tex:

\chapter
This chapter
\section
This section. \cite{boyd08,pam09}
\renewcommand{\bibsection}{\topskip=1in\chapter*{REFERENCES}\topskip=0in \addcontentsline{toc}{chapter}{REFERENCES}}
\bibliographystyle{unsrtnat}
\bibliography{chap2}

This is my code. The first chapter should contain 80 citations, whereas the second chapter should have 40 citations. But each chapter has its own reference section, which contains all 120 citations. Is there any solution to it? Thanks.