A coated article is provided which may be heat treated (e.g., thermally tempered) in certain instances. In certain example embodiments, an interlayer of or including a metal oxide such as tin oxide is provided under an infrared (IR) reflecting layer so as to be located between respective layers comprising silicon nitride and zinc oxide. It has been found that the use of such a tin oxide inclusive interlayer results in significantly improved mechanical durability, thermal stability and/or haze characteristics.