How to include list of abbreviations in the table of contents

Question

In fact I want to include my list of abbreviations in my table of contents. But when I write my latex code this list of abbreviations isn't showed in the table of contents. I have used \nomenclature which will automatically print that nomenclature in the list of abbreviations which were displayed using \renewcommand{\nomname}{List of abbreviations}. Here is the code:

\documentclass[12pt]{report}
\usepackage{lipsum}
\usepackage[french]{babel}
\usepackage{unnumberedtotoc}
\usepackage[automark,
plainheadsepline,
headsepline,
plainfootsepline,
footsepline,
markcase=ignoreupper]{scrlayer-scrpage}
\clearpairofpagestyles
\ihead*{\leftmark}
\cfoot*{\pagemark}
\setkomafont{pageheadfoot}{\scshape}
\usepackage{titlesec}
\usepackage[a4paper,right=20mm,left=25mm,top=25mm, bottom=26mm,%
head=14.5pt,%<- new 
]{geometry}
\titleformat{\chapter}[display] 
{\normalfont\huge\bfseries}{\chaptertitlename\ \thechapter}{20pt}{\Huge}
\titlespacing*{\chapter}{0pt}{0pt}{20pt}
\titleformat{\paragraph}
{\normalfont\normalsize\bfseries}{\theparagraph}{1em}{}
\titlespacing*{\paragraph}
{0pt}{3.25ex plus 1ex minus .2ex}{1.5ex plus .2ex}
\begin{document}
\tableofcontents
\addchap{Publications}
\addchap{Acknowledgement}
\renewcommand{\nomname}{List of abbreviations}
\chapter{Introduction}
\lipsum
\lipsum
\chapter{state of art}
\lipsum
\chapter{theory}
\lipsum
\end{document}