documentclass[
    12pt,
    oneside,
    a4paper,
    english,
    french,
    spanish,
    brazil
    ]{abntex2}
usepackage{graphicx}
usepackage{float}
usepackage{tikz}
usetikzlibrary{calc, shapes}

begin{document}

begin{figure}[H]
centering
tikzset{thick,
         tree node/.style = {align=center, inner sep=0pt, font = scriptsize},
every label/.append style = {font=scriptsize},
                 S/.style = {draw, circle, minimum size = 20mm, inner sep=0pt,
                             top color=white, bottom color=blue!20},
               ENL/.style = {% edge node left
                             font=footnotesize, left=1pt},
               ENR/.style = {% edge node right
                             font=footnotesize, right=1pt},
                     grow = down,
         sibling distance = 2.8cm,
           level distance = 3cm
           }
begin{tikzpicture}
node [S, label= 2:Some text here] {$PL0$}
    child{node [S] {$PL1$}
            child{node [S] {$PL3$}
            edge from parent node[ENL] {$x2 leq 2$}}
            child{node [S] {$PL4$}
                 child{node [S] {$PL5$}
                     child{node [S] {$PL7$}
                     edge from parent node[ENL] {$x2 leq 3$}}
                     child{node [S, label = 2:More text here] {$PL8$}
                     edge from parent node[ENR] {$x2 geq 4$}}
          edge from parent node[ENL] {$x1 leq 3$}}
          child{node [S, label = 2:Another text here] {$PL6$}
          edge from parent node[ENR] {$x1 geq 4$}}
            edge from parent node[ENR] {$x2 geq 3$}}
    edge from parent node[ENL] {$x1 leq 4$}}
    child{node [S, label = 2:Last text here] {$PL2$}
    edge from parent node[ENR] {$x1 geq 5$}};
end{tikzpicture}
        caption{My Figure.}
end{figure}

end{document}