These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.62 s (backtrack: 0/20).

[ebuild   R    ] app-misc/mime-types-2.1.54::gentoo  USE="nginx*" 29 KiB
[ebuild  N     ] acct-group/nginx-0-r2::gentoo  0 KiB
[ebuild  N     ] acct-user/nginx-0-r2::gentoo  USE="-icingaweb2 -mgraph" 0 KiB
[ebuild  N     ] dev-libs/yajl-2.1.0-r6:0/2::gentoo  83 KiB
[ebuild  N     ] dev-libs/modsecurity-3.0.16:0/3::gentoo  USE="json -doc -fuzzyhash -geoip -geoip2 -lmdb -lua" LUA_SINGLE_TARGET="lua5-1 -lua5-3 -lua5-4" 11509 KiB
[ebuild  N     ] www-servers/nginx-1.31.7:0/1.31.7::gentoo  USE="aio http modules -debug -libatomic -mail (-selinux) -stream -test" NGINX_MODULES_HTTP="access auth_basic autoindex browser charset empty_gif fastcgi geo grpc gzip limit_conn limit_req map memcached mirror proxy referer rewrite scgi split_clients ssi ssl upstream_hash upstream_ip_hash upstream_keepalive upstream_least_conn upstream_random upstream_zone userid uwsgi v2 -addition -auth_request -dav -degradation -flv -geoip -gunzip -gzip_static -image_filter -mp4 -perl -random_index -realip -secure_link -slice -stub_status -sub -v3 -xslt" NGINX_MODULES_MAIL="imap pop3 smtp ssl" NGINX_MODULES_STREAM="access geo limit_conn map pass return set split_clients ssl upstream_hash upstream_least_conn upstream_random upstream_zone -geoip -realip -ssl_preread" 1360 KiB
[ebuild  N     ] www-nginx/ngx-modsecurity-1.0.4::gentoo  1135 KiB

Total: 7 packages (6 new, 1 reinstall), Size of downloads: 14114 KiB

The following USE changes are necessary to proceed:
 (see "package.use" in the portage(5) man page for more details)
# required by www-servers/nginx-1.31.7::gentoo
# required by www-nginx/ngx-modsecurity-1.0.4::gentoo
# required by =www-nginx/ngx-modsecurity-1.0.4 (argument)
>=app-misc/mime-types-2.1.54 nginx