Preheat your oven to 350°F (175°C). Grease and flour a 9x5-inch loaf pan, or line with parchment paper, leaving some overhang on the sides for easy removal.
In a medium bowl, whisk together the flour, baking soda, salt, and all spices (cinnamon, cardamom, ginger, cloves, nutmeg, and allspice) for at least 30 seconds to ensure even distribution.
In a large bowl, beat the softened butter with both sugars until light and fluffy, about 3-4 minutes.
Add eggs one at a time, beating well after each addition. Stir in vanilla extract and Greek yogurt or sour cream until just combined.
Gradually fold the dry ingredients into the wet mixture, stirring just until combined. Stop when you no longer see dry flour (typically 12-15 folds with a spatula is perfect).
Gently fold in the diced apples and nuts (if using). For optimal moisture distribution, consider coating your apple pieces with a light dusting of flour before adding.
Pour the batter into your prepared loaf pan and smooth the top. Bake for 55-60 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs. If the top begins to brown too quickly, tent with aluminum foil after about 35-40 minutes.
Allow the bread to cool in the pan for 15 minutes before transferring to a wire rack to cool completely, about 30 more minutes.
For the optional chai glaze, whisk together powdered sugar, cooled chai tea, and vanilla until smooth, then drizzle over the bread once it's completely cooled.