In the bowl of a stand mixer, whisk together flour, brown sugar, salt, yeast, and cinnamon by hand until combined.
In a small saucepan, heat milk, sweet potato, and butter over medium heat, stirring frequently, until butter is melted and an instant-read thermometer registers 120°F (49°C) to 130°F (54°C). Add hot milk mixture and 1 egg (50 grams) to flour mixture; using the paddle attachment, beat at low speed until a shaggy dough forms. Switch to the dough hook attachment; beat at medium-low speed until dough pulls away from sides of bowl, 8 to 12 minutes.
Lightly spray a large bowl with cooking spray. Place dough in bowl, turning to grease top. Cover and let rise in a warm, draft-free place (75°F/24°C) until doubled in size, 45 minutes to 1 hour.
Punch down dough, and turn out onto a lightly floured surface. Flatten into a 1-inch-thick circle, and add chocolate chips. Gently knead until chocolate is completely incorporated. Cover and let stand for 20 minutes.
Pat dough into a 10×8-inch rectangle, with one short side closest to you. Fold bottom third of dough over center third; starting at short side where dough is folded, roll up dough into a log. Pull log, seam side down, toward you to create tension on surface.
Lightly spray a 9×5-inch loaf pan with baking spray with flour. Place dough, seam side down, in prepared pan, tucking ends slightly. Cover and let rise in a warm, draft-free place (75°F/24°C) until doubled in size and risen just above sides of pan, 1 to 1½ hours.
Preheat oven to 350°F (180°C).
In a small bowl, whisk together 1 tablespoon (15 grams) water and remaining 1 egg (50 grams). Brush egg wash on top of dough.
Bake until golden brown and an instant-read thermometer inserted in center registers at least 190°F (88°C), 35 to 40 minutes. Let cool in pan for 5 minutes. Remove from pan, and let cool completely on a wire rack. Store in an airtight container for up to 5 days.